Related Experiment Video
Updated: Jul 27, 2025
High Throughput Microinjections of Sea Urchin Zygotes
Published on: January 21, 2014
Effect on Inhibition of Micromere Segregation on the Mitotic Pattern in the Sea Urchin Embryo: (micromeres/mitotic
Silvana Filosa1, Piero Andreuccetti1, Elio Parisi2
1Istituto di Istologia ed Embriologia, University of Naples. 80131, Naples.
Abstract:
Detergent treatment of sea urchin eggs at the mid 4-cell stage results in prevention of micromere segregation at the fourth cleavage. In these embryos not only the formation of the primary mesenchyme is suppressed, but synchrony of cell division, which is the rule during the first four cleavage cycles, continues for several cycles after the 16-cell stage while the typical mitotic phase wave that sets in after micromere segregation is abolished. These results support the hypothesis that micromeres act as coordinators of the mitotic activity of the embryo.
Insights
Detergent treatment prevents sea urchin micromere segregation, suppressing primary mesenchyme formation. This finding suggests micromeres coordinate early embryonic cell division timing.
Area of Science:
- Developmental biology
- Cell biology
- Marine biology
Background:
- Sea urchin embryos undergo rapid, synchronous cell divisions during early cleavage.
- Micromeres, a specific cell type, form at the 4th cleavage and are crucial for development.
- The role of micromeres in coordinating mitotic timing is not fully understood.
Purpose of the Study:
- To investigate the role of micromeres in coordinating mitotic activity during sea urchin embryogenesis.
- To determine the effects of preventing micromere segregation on early embryonic development.
Main Methods:
- Sea urchin eggs were treated with detergent at the mid 4-cell stage to inhibit micromere segregation.
- Embryos were observed to assess cell division synchrony and mitotic phase progression.
- Primary mesenchyme formation was monitored as an indicator of developmental progression.
Main Results:
- Detergent treatment prevented micromere segregation at the fourth cleavage.
- Primary mesenchyme formation was suppressed in treated embryos.
- Cell division synchrony persisted beyond the 16-cell stage, and the typical mitotic phase wave was abolished.
Conclusions:
- Micromere segregation is essential for establishing the normal pattern of mitotic activity in sea urchin embryos.
- These findings support the hypothesis that micromeres act as coordinators of embryonic mitotic activity.
- Disruption of micromere formation significantly impacts developmental timing and cell fate.
